Problem: The enthalpy of combustion of hard coal averages −35 kJ/g, that of gasoline, 1.28 x 105 kJ/gal. How many kilograms of hard coal provide the same amount of heat as is available from 1.0 gallon of gasoline? Assume that the density of gasoline is 0.692 g/mL (the same as the density of isooctane).

Problem Details

The enthalpy of combustion of hard coal averages −35 kJ/g, that of gasoline, 1.28 x 105 kJ/gal. How many kilograms of hard coal provide the same amount of heat as is available from 1.0 gallon of gasoline? Assume that the density of gasoline is 0.692 g/mL (the same as the density of isooctane).